12,744 research outputs found
Simulation or cohort models? Continuous time simulation and discretized Markov models to estimate cost-effectiveness
The choice of model design for decision analytic models in cost-effectiveness analysis has been the subject of discussion. The current work addresses this issue by noting that, when time is to be explicitly modelled, we need to represent phenomena occurring in continuous time. Multistate models evaluated in continuous time might be used but closed form solutions of expected time in each state may not exist or may be difficult to obtain. Two approximations can then be used for costeffectiveness estimation: (1) simulation models, where continuous time estimates are obtained through Monte Carlo simulation, and (2) discretized models. This work draws recommendations on their use by showing that, when these alternative models can be applied, it is preferable to implement a cohort discretized model than a simulation model. Whilst the bias from the first can be minimized by reducing the cycle length, the second is inherently stochastic. Even though specialized literature advocates this framework, the current practice in economic evaluation is to define clinically meaningful cycle lengths for discretized models, disregarding potential biases.
The Elephant Quantum Walk
We explore the impact of long-range memory on the properties of a family of
quantum walks in a one-dimensional lattice and discrete time, which can be
understood as the quantum version of the classical "Elephant Random Walk"
non-Markovian process. This Elephant Quantum Walk is robustly superballistic
with the standard deviation showing a constant exponent, , whatever the quantum coin operator, on which the diffusion coefficient is
dependent. On the one hand, this result indicates that contrarily to the
classical case, the degree of superdiffusivity in quantum non- Markovian
processes of this kind is mainly ruled by the extension of memory rather than
other microscopic parameters that explicitly define the process. On the other
hand, these parameters reflect on the diffusion coefficient.Comment: 4 figures, any comments is welcome. Accepted in PR
RelatĂłrio final de consultoria (IICA/PRODETAB).
Cultivo in vitro de tecidos do carrapato Boophilus microplus e obtenção de imunĂłgenos. Desenvolvimento de um teste de imunocromatografia para detecção de anticorpos contra Babesia bigemina. Imunidade conferida pela membrana externa dos corpĂșsculos iniciais de Anaplasma marginale e proteĂnas principais da superfĂcie MSP-2 E MSP-5, associadas a indutor inespecĂfico de imunidade celular em bovinos.bitstream/item/136446/1/DOC-94.pd
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